1. Field of the Invention
The field of the invention relates to a process for binding pamphlets, catalogs and similar bound products made from folded printed sheets. These products are normally made by means of an adhesive binding apparatus, wherein the printed sheets are combined in a block, the front and back sides of the cover are deposited, the cover edges and the back of the block are coated with an adhesive and a spine fold is brought to the block and bonded to it from a spine fold station associated with the adhesive binding apparatus.
2. Description of the Related Technology
In recent years, the use and importance of publications such as pamphlets has dramatically increased. To keep pace with this increase, methods for rapid, inexpensive production of large numbers of high quality publications are necessary.
A common process for binding involves numerous distinct operations. It begins by inserting folded or rotation folded sheets into the sheet magazine of a gathering machine that has been previously set up. The gathering machine combines the sheets into a block. A special machine, in a separate operation, brings together cover sheets and an unprinted longitudinal spine, adhesively binds them together, and presses them. The assembled cover then goes to a spine printing machine, it is then dried and transported to a gathering machine. The gathering machine combines one side of the cover with the block, and an adhesive machine glues them together. A second gathering machine is used to assemble the block and the other cover.
This process requires a series of steps of a highly different nature. It is necessary to carry out the gathering of the front and back side of the cover on separate machines. The adhesive bonding and drying of the spine fold is done separately. A further working step is transporting the product to a print shop merely to print the spine fold on the future back side and on one edge of the back side of the cover.
Printing the covers creates several problems which can be resolved only at great expense. The front and back sides of the cover do not meet; they are spaced apart by the glued on longitudinal spine at a distance corresponding to the block to be inserted later. This forces the printing process to be carried out on surfaces with differing areas: one surface is the size of only one cover, and the other surface is the size of the other cover and the spine.
When printing the spine and the covers together, most of the ink is rolled around the roll if only a small quantity of ink is deposited in the printing process. The ink therefore runs "dead" on the rolls. As a result, the ink emulsifies, and its drying properties change in an unfavorable direction, i.e. the drying time of the ink is considerably increased. These problems were resolved at considerable cost.
The problems relative to the double transport were not overcome. Rather, it is necessary to use especially developed pallets to transport the covers.
In a sequence of processing steps for the manufacture of a product, the inherent errors are additive; they may be reduced by a commensurate effort, but cannot be excluded.
In the process of gathering and bonding the front and back parts of the cover with the spine fold, it is necessary to exactly coordinate the parts relative to each other. The printing process requires a further appropriate alignment. Finally, a third alignment must be carried out during the adhesive bonding of the cover to the block. There are therefore three independent sources of defects in alignment. Any one of these defects could result in a very poor quality product or even make it unusable.
DE-AS 1 093 775 discloses a machine for the bonding of endless printed strips to books. For an adhesive binding apparatus with a high hourly output these strips are not suitable, as frequent replacement of the empty rolls is necessary, leading to long downtimes for the entire installation.